NEWCASTLE UPON TYNE, UK -- An exotic type of crab is spreading at an alarming rate throughout Britain's coast and rivers, a study by the University's School of Marine Science and Technology has found.

The Chinese mitten crab, brought to Britain during the last century in ships' ballast water, could cause devastating environmental problems if populations are not monitored and controlled, say the study's authors.

The study details how the UK colonisation of mitten crabs has increased on a large scale in recent years. The researchers carried out the first comprehensive modelling of the crab's migration through Europe and the UK. They compared the two and found the pattern of the crabs' ongoing invasion of the UK is similar to the population expansion in Europe earlier in the last century when the Continent experienced a major outbreak.

The study authors predict that the mitten crab - so called because its claws are coated with small clumps of dark brown fur, or mittens - has the potential to establish itself in all major UK estuaries in several years time.

Mitten crabs are unwelcome because they prey on protected UK native species such as the white-clawed crayfish and salmon eggs and fry. They also settle in river banks, burrowing into them and riddling them with bore holes up to half a metre long which may eventually cause the bank to collapse.

The study, published in the academic journal Biological Invasions, recommends that a nationwide monitoring and trapping system for the crab should be introduced before it is too late to control the population.

Chinese mitten crabs are already present in some of our waterways, including the Thames, Humber and Tyne rivers and parts of the North Sea and Channel coasts.

Dr Matt Bentley, one of the research team, said: 'The pattern of the spread in the UK since the 1970s mirrors the spread in mainland Europe and in the Baltic region which experienced a major outbreak. This is a fairly good indication that the UK is set for a similar situation.'

'With most invasive species, such as the grey squirrel, the problem is not recognised until it is too late to do anything and you can not eliminate it without taking drastic environmental measures.'

The research team also included Professor Tony Clare and Dr Steve Rushton at Newcastle University and Dr Leif-Matthias Herborg, formerly of Newcastle University and now at the University of Windsor (Ontario, Canada).

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